Abstract: A method can include receiving seismic data responsive to stimulation of an anisotropic formation via a well disposed in the formation; receiving crosswell calibrated velocity model information that spans a depth range of the anisotropic formation; locating a microseismic event generated by the stimulation based at least in part on a portion of the received seismic data and based at least in part on the crosswell calibrated velocity model information; and rendering the located microseismic event to a display with respect to one or more dimensions of the anisotropic formation.

Abstract: A seismic system that includes a seismic source configured to generate a first seismic signal and a second seismic signal in a formation adjacent the seismic source. A first downhole sensing device disposed in a first borehole configured to detect the first seismic signal and the second seismic signal in the formation; and a first surface acquisition system is in communication with the first downhole sensing device. The first surface acquisition system is configured to: determine a first reference transit time based at least in part on detection of the first seismic signal by the first downhole sensing device; a first subsequent transit time based at least in part on detection of the second seismic signal by the first downhole sensing device; and whether a synchronization variation is expected to be present based at least in part on the first reference transit time and the first subsequent transit time.

Abstract: A device can include a housing; external electrodes; circuitry disposed in the housing where the circuitry converts analog signals sensed by the external electrodes to digital signals. Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: Systems and methods for deploying and using a controlled-frequency downhole seismic source are provided. A downhole seismic source may be placed into a borehole in a geological formation and coupled rigidly to the geological formation via an edge of the borehole. A controlled-frequency seismic signal may be generated sufficient to enable a seismic measurement of the geological formation.

Abstract: A method can include receiving seismic data responsive to stimulation of an anisotropic formation via a well disposed in the formation; receiving crosswell calibrated velocity model information that spans a depth range of the anisotropic formation; locating a microseismic event generated by the stimulation based at least in part on a portion of the received seismic data and based at least in part on the crosswell calibrated velocity model information; and rendering the located microseismic event to a display with respect to one or more dimensions of the anisotropic formation.

Abstract: A seismic system that includes a seismic source configured to generate a first seismic signal and a second seismic signal in a formation adjacent the seismic source. A first downhole sensing device disposed in a first borehole configured to detect the first seismic signal and the second seismic signal in the formation; and a first surface acquisition system is in communication with the first downhole sensing device. The first surface acquisition system is configured to: determine a first reference transit time based at least in part on detection of the first seismic signal by the first downhole sensing device; a first subsequent transit time based at least in part on detection of the second seismic signal by the first downhole sensing device; and whether a synchronization variation is expected to be present based at least in part on the first reference transit time and the first subsequent transit time.

Abstract: Systems and methods for deploying and using a controlled-frequency downhole seismic source are provided. A downhole seismic source may be placed into a borehole in a geological formation and coupled rigidly to the geological formation via an edge of the borehole. A controlled-frequency seismic signal may be generated sufficient to enable a seismic measurement of the geological formation.

Abstract: A device can include a housing; external electrodes; circuitry disposed in the housing where the circuitry converts analog signals sensed by the external electrodes to digital signals. Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: A method of mapping a subterranean formation having at least one wellbore therein may include operating an electromagnetic (EM) signal source and an EM receiver to generate wellbore position data. The method may also include operating a seismic signal source and a seismic receiver to generate seismic data, and generating subterranean formation data based upon the wellbore position data and the seismic data.

Abstract: One embodiment of the invention involves a model-based method of inverting electromagnetic data associated with a subsurface area that includes developing a three-dimensional electromagnetic property model of the area, and restricting changes that may be made to the model during the electromagnetic data inversion process. Other related embodiments of the inventive method are also described and claimed.

Abstract: One embodiment of the invention involves a method for determining whether an electromagnetic survey will be able to distinguish between different subsurface conditions in an area that includes developing a three-dimensional electromagnetic property model of the area, and simulating an electromagnetic response of a field electromagnetic data acquisition system using the three-dimensional electromagnetic property model to determine if expected differences in an electromagnetic response of a electromagnetic data acquisition system are within detectability limits of the system. Another embodiment involves a model-based method of inverting electromagnetic data associated with a subsurface area that includes developing a three-dimensional electromagnetic property model of the area, and restricting changes that may be made to the model during the electromagnetic data inversion process. Other related embodiments of the inventive method are also described and claimed.